Yes, Emma does take on a superior attitude with Mr. Martin. There is something dangerous in Emma's ability to be charming, lively and likable by all who know her on the one hand and manage manipulability so adroitly on the other. When we see this superior class attitude in Mr. Darcy it is not diluted with charm so one knows what to expect. With Emma, she is able to get away with too much in my opinion and with no resistance except, thus far, from Mr. Knightley. Charm in Austen's characters is usually a sign to be wary. Is the person using it in a manipulative or selfish way, one should ask? Emma is totally manipulating Harriet's good opinion of a fine young man who does not deserve to be demeaned in such a way and merely to suit Emma's wishes to match Harriet to Mr. Elton. We are told she's intelligent and clever; she knows exactly what she is doing. Her beatdown of Mr. Martin to get Harriet to transfer her good opinion from him to Mr. Elton is one of the most skillful things I've seen in a long time. (Exquisite writing on JA's part, I must say) No wonder Austen said Emma would probably be a character who would not be much liked; she has her doing such mean things---the mean girl syndrome, if you will. Emma certainly has her positive traits to be sure. It is difficult to erase all knowledge of her from the entire book but in the confines of the first six chapters she has a long way to go to earn my respect as heroine to truly like from the inside out.